A word introverts use whenever they are asked why they are so shy and why won't they stop being so shy.

Merely translates to "I don't know why I am this way. When I'm out with people, I wish I was home and alone. When I'm home and alone, I wish I was out with people. It's a horrible loop. There's no explaining my strange ways, and I'm trying to better myself with every chance I get, but you getting frustrated with me won't help at all. I appreciate you taking me places and making an effort. But please, unless you suffer the same anxiety I do, stop being mad at me for my social difficulties. I will get there when the time's right. In the mean time, please try to understand why I'm like this."